i think across the board they use the number.
I know the S-Shell bushings I have are numbered to the hole size,,,, ie #496 is .496
I never thought about it dropping like 18grs of red-dot and 496grs of bulls-eye.... LOL
anyway my post was simply to point out that if worse come to worst it would be a pretty simple matter to have some rod [10' worth] chopped to length and then drilled at home.
or to purchase 20 of the smallest ones available and drilled to size as needed.